Varicose veins in lower limbs is one of the most common vascular diseases. Venous valves in humans are normally bicuspid valves in which each valve cusp forms a reservoir for blood under pressure which forces the free edges of the cusps together to prevent reflux. Incompetence is a condition in which the cusps do not properly approach each other when a pressure differential or gradient is applied across a valve permitting reflux or retrograde flow of blood to occur. Medical literature indicates that many physicians believe that chronic venous insufficiency (CVI) of the lower limbs is the result of deep venous thrombosis (DVT) with associated inflammatory changes of venous valve cusps. Varicose veins often occur in the long saphenous veins in the medial part of the legs when valve incompetence occurs. A varicose vein is considered to be a condition which occurs when a vein dilates and the tributaries become elongated and tortuous, resulting in cosmetic impairment, inflammatory phlebitis, pain and thrombosis.
When the valves of the varicose, long saphenous vein are examined, changes are evident including dilation, evagination between the cusps, and in later stages the membrane between the commissures become thin and may have numerous fenestrae. These conditions are generally termed venous valve incompetence.
One of the most frequent symptoms of incompetence is poor coaptation of the valve cusps due to floppiness of the leading edges of the valve cusps. Reflux of blood flow occurs both along the free edges of the cusps and in the corneal areas.
Venous valve reconstruction has progressed to the point that competence can be achieved by both internal and external repair techniques.
In most cases varicose veins in lower limbs occurs due to insufficiency of the SFJ. In different countries of the World, on the average, from 40% to 60% of the female population over age 40 are affected by lower limb varicosity. It is also very important to save these veins for potential application thereof in aorto-coronary bypass or peripheral arterial reconstructions.
So far no efficient methods have been developed for the elimination of valve incompetence (insufficiency) and saving the superficial and deep veins, especially in the SFJ area. One of the surgical procedures to address this problem is application of sutures to the edges of the valve cusp leaflets in the corneal areas. The sutures are then pulled back and tied to the walls of the vein in order to reduce the length of the coapting edges of the leaflets. For example, the “Atlas of Venous Surgery (1992), at page 125, discusses various valve reconstruction techniques for primary valve insufficiency. One technique is entitled “Internal Technique by Transvalvular Venotomy” involves first laying open the valve by performing a venotomy to expose the valve. The object of the repair is to shorten the leading edge of each cusp to restore a cup-like configuration to both cusps in a procedure termed internal valvuloplasty. The valve is repaired with monofilament sutures at three locations (medial, lateral and posterior) until the leading edges of two valves lie gently across the face of the vein with the floppy, rugal folds eliminated.
The simplest and most effective solution of the problem is an external compression of the veins around the incompetent valves by extravenous corrector to reduce their central opening lumen and to restore valves function.
There are many engineering solutions applied in medicine for correcting defects in blood vessels and human hollow organs.
Devices and methods are known for reconstructions of effected blood vessels (U.S. Pat. No. 5,100,422 or “Venous Disorders” by John B. BERGAN and James S. T. YAO, W.B. Saunders Company, Philadelphia, 1991, p. 303-311).
Devices are also known for compression of vessels or hollow organs or securing portable medical instruments thereon (U.S. Pat. Nos. 5,160,338; 5,080,095; 5,171,252 or 4,938,765).
Such devices can compress the vein around the incompetent valve and control, within certain limits, the compression force. However, these devices cannot be disposed directly on a venous junction, and they do not provide the desired accuracy in compression rate control.
Special devices are further known for occuring the vein (U.S. Pat. Nos. 4,586,501 or 4,531,519) applied in surgery. They provide a more accurate control of the vein compression rate. However, they cannot be secured directly on the venous junction. Besides, they are complex in design (with a remote pressure source) and relatively large-sized, so they cannot constantly and independently operate inside the human body.
Most similar to the present invention in the device disclosed in U.S. Pat. No. 5,120,300 and in the book “Plastric and reconstructive operations on great veins”, by A. N. Vedensky, “Medizina”, Leningrad, 1979, p. 186-194. Such devices comprise bands (U.S. Pat. No. 5,120,300) or spiral springs formed of plastic, metal, alloy or plastic reinforced with metal (lavsan, fluorineplastic etc.).
The common drawback of all devices described above is follows: they cannot be applied for correction of vein valves, disposed in the venous junctions.